Chapter Exam

Chapter 9: Microbes in Human Welfare — Online MCQ Test

Q: Which microorganism is commonly used in the production of curd from milk?

Answer: A. Lactobacillus — Lactobacillus converts milk sugar into lactic acid, which helps in curd formation. It is a lactic acid bacterium used in household fermentation.

Q: Which of the following is used in bread and beer production?

Answer: B. Yeast — Yeast, especially Saccharomyces cerevisiae, ferments sugars to produce carbon dioxide and alcohol. This makes it useful in bread and beer preparation.

Q: In sewage treatment, the activated sludge is mainly rich in:

Answer: C. Flocs of bacteria — Activated sludge contains flocs mainly made of bacteria along with fungal filaments. These microbes help decompose organic wastes in sewage.

Q: Which of the following is NOT correctly matched?

Answer: D. Antibiotic production - Rhizobium — Rhizobium is a nitrogen-fixing bacterium, not an antibiotic-producing organism. Antibiotics are generally produced by microbes like Streptomyces and Penicillium.

Q: Which option correctly identifies the organism and its product used in genetic engineering and pest control?

Answer: B. Bacillus thuringiensis - Bt toxin — Bacillus thuringiensis produces Bt toxin, which is used in biopesticides and transgenic crops. The other options are mismatched with their products or functions.

ZOOLOGY · CLASS 12th · Tamil Nadu State Board

Practice Chapter 9: Microbes in Human Welfare with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 12th ZOOLOGY. This chapter covers: Focusing on practical biological applications this chapter details microbial roles in household products industrial fermentation sewage treatment biogas production and pest control.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 9: Microbes in Human Welfare — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 12th ZOOLOGY — Chapter 9: Microbes in Human Welfare, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which microorganism is commonly used in the production of curd from milk?

A. Lactobacillus ✓
B. Saccharomyces
C. Rhizobium
D. Plasmodium

Answer: A. Lactobacillus
Lactobacillus converts milk sugar into lactic acid, which helps in curd formation. It is a lactic acid bacterium used in household fermentation.

Which of the following is used in bread and beer production?

A. Bacteria
B. Yeast ✓
C. Algae
D. Protozoa

Answer: B. Yeast
Yeast, especially Saccharomyces cerevisiae, ferments sugars to produce carbon dioxide and alcohol. This makes it useful in bread and beer preparation.

In sewage treatment, the activated sludge is mainly rich in:

A. Viruses
B. Protozoans
C. Flocs of bacteria ✓
D. Fungi only

Answer: C. Flocs of bacteria
Activated sludge contains flocs mainly made of bacteria along with fungal filaments. These microbes help decompose organic wastes in sewage.

Which of the following is NOT correctly matched?

A. Curd formation - Lactobacillus
B. Biogas production - Methanogens
C. Cheese ripening - Penicillium
D. Antibiotic production - Rhizobium ✓

Answer: D. Antibiotic production - Rhizobium
Rhizobium is a nitrogen-fixing bacterium, not an antibiotic-producing organism. Antibiotics are generally produced by microbes like Streptomyces and Penicillium.

Which option correctly identifies the organism and its product used in genetic engineering and pest control?

A. Rhizobium - curd
B. Bacillus thuringiensis - Bt toxin ✓
C. Aspergillus niger - penicillin
D. Saccharomyces cerevisiae - nitrogen fixation

Answer: B. Bacillus thuringiensis - Bt toxin
Bacillus thuringiensis produces Bt toxin, which is used in biopesticides and transgenic crops. The other options are mismatched with their products or functions.

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